Abstract: The operator of a taphole drilling apparatus for blast furnaces performs manual changes on the apparatus in its safe position of rest and operation by remote control and automatic latching in hazardous taphole work including drilling and subsequent driving, release, and extraction of a tap bar. The usual guide rail (22) carrying reciprocably a hammer drill (30) thereon incorporates a remotely openable automatically latching centralizer (42) at its forward end and an extraction carriage (29) on which, after removal of the drill steel (43), an impact sleeve (50) can be manually mounted for being impacted by the hammer drill (30). In one mounting position (FIG. 5) of the impact sleeve (50), a latch (57) therein is biased to automatically latch the shank of a tap bar (53) thereto for extraction by impacts. In a 180.degree. counter-turned position the latch (57) will fall aside and the mounted sleeve (50) is used to drive the tap bar while guided by the centralizer (42).